I have 2 Cooler Master R4 fans cooling my dual 120mm radiator at the top of my case. One of these is connected to the CPU fan header on the motherboard while the other one is connected to the pwr_fan header (since I have no more fan headers left). However, both of these fans are running at 1,800+ RPM (they are rated for 2,000rpm) even when the system is idle. I have tried going into the BIOS to change the fan speeds but the ASUS Qfan control does not seem to have any options for this. SpeedFan also only works for my rear chassis case and not my rad fans for some reason. Is there any way to make these fans run at a slower or quieter setting?
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The Cooler Master R4 fans have a 3 pin connector, hence their fan speed cannot be controlled via Motherboard/BIOS. You'd have to invest in a fan controller.
I thought that 3 pin fans can still be controlled by limiting the voltage that they receive while 4 pin fans use PWM control.